Notes

#include "I2Cdev.h"

#include "MPU6050_6Axis_MotionApps20.h"

#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
#include "Wire.h"
#endif


MPU6050 mpu;

#define OUTPUT_READABLE_YAWPITCHROLL

#define LED_PIN 13
bool blinkState = false;

// MPU control/status vars
bool dmpReady = false; // set true if DMP init was successful
uint8_t mpuIntStatus; // holds actual interrupt status byte from MPU
uint8_t devStatus; // return status after each device operation (0 = success, !0 = error)
uint16_t packetSize; // expected DMP packet size (default is 42 bytes)
uint16_t fifoCount; // count of all bytes currently in FIFO
uint8_t fifoBuffer[64]; // FIFO storage buffer

// orientation/motion vars
Quaternion q; // [w, x, y, z] quaternion container
VectorInt16 aa; // [x, y, z] accel sensor measurements
VectorInt16 aaReal; // [x, y, z] gravity-free accel sensor measurements
VectorInt16 aaWorld; // [x, y, z] world-frame accel sensor measurements
VectorFloat gravity; // [x, y, z] gravity vector
float euler[3]; // [psi, theta, phi] Euler angle container
float ypr[3]; // [yaw, pitch, roll] yaw/pitch/roll container and gravity vector

// packet structure for InvenSense teapot demo
uint8_t teapotPacket[14] = { '$', 0x02, 0,0, 0,0, 0,0, 0,0, 0x00, 0x00, 'r', 'n' };
//*************************************************************************************************************************************************************************
// Variables

float OldP = 0; // Previous value used to calculate change in P // DELTA P
float P = 0; // Proportional component
float I = 0; // Integral just the sum of P over time
float OldI = 0; // previous value of I for calculation of Delta I
float D = 0; // Differential D = P - OldP
float bp = -60; // balance point
float pwm = 0; // value of Pulse Width Modulation to ENA ENB
long a = 0; // L298N to IN 1 to 4
long b = 0; //
const int PinR1 = 8; // arduino pin 5 to l298 pin IN4
const int PinR2 = 7; // arduino pin 6 to l298 pin IN3
const int PinL1 = 5; // arduino pin 7 to l298 pin IN1
const int PinL2 = 6; // arduino pin 8 to l298 pin IN2
const int PwmR = 9; // arduino pin 9 to l298 pin ENB
const int PwmL = 10; // arduino pin 10 to l298 pin ENA
//****************************************************************************************************************************************************


// ================================================================
// === INTERRUPT DETECTION ROUTINE ===
// ================================================================

volatile bool mpuInterrupt = false; // indicates whether MPU interrupt pin has gone high
void dmpDataReady() {
mpuInterrupt = true;
}



// ================================================================
// === INITIAL SETUP ===
// ================================================================

void setup() {
//*********************************************************************************************************************************************************
// arduino to l298 pins hopefully self explanatory
pinMode(PinR1,OUTPUT);
pinMode(PinR2,OUTPUT);
pinMode(PinL1,OUTPUT);
pinMode(PinL2,OUTPUT);
//**********************************************************************************************************************************************************
// join I2C bus (I2Cdev library doesn't do this automatically)
#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
Wire.begin();
TWBR = 24; // 400kHz I2C clock (200kHz if CPU is 8MHz)
#elif I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_FASTWIRE
Fastwire::setup(400, true);
#endif

// initialize serial communication
Serial.begin(57600);
while (!Serial); //

// initialize device
Serial.println(F("Initializing I2C devices..."));
mpu.initialize();

// verify connection
Serial.println(F("Testing device connections..."));
Serial.println(mpu.testConnection() ? F("MPU6050 connection successful") : F("MPU6050 connection failed"));


// load and configure the DMP
Serial.println(F("Initializing DMP..."));
devStatus = mpu.dmpInitialize();

// supply your own gyro offsets here, scaled for min sensitivity
//****************************************************************************************************************************************
// use calibration program to get your own values
mpu.setXGyroOffset(70);//(220);
mpu.setYGyroOffset(42);//(76);
mpu.setZGyroOffset(-100);//(-85);
mpu.setXAccelOffset(17084);//(1788); // 1688 factory default for my test chip
mpu.setYAccelOffset(304);
mpu.setZAccelOffset(420);
//****************************************************************************************************************************************
// make sure it worked (returns 0 if so)
if (devStatus == 0) {
// turn on the DMP, now that it's ready
Serial.println(F("Enabling DMP..."));
mpu.setDMPEnabled(true);

// enable Arduino interrupt detection
Serial.println(F("Enabling interrupt detection (Arduino external interrupt 0)..."));
attachInterrupt(0, dmpDataReady, RISING);
mpuIntStatus = mpu.getIntStatus();

// set our DMP Ready flag so the main loop() function knows it's okay to use it
Serial.println(F("DMP ready! Waiting for first interrupt..."));
dmpReady = true;

// get expected DMP packet size for later comparison
packetSize = mpu.dmpGetFIFOPacketSize();
} else {
// ERROR!
// 1 = initial memory load failed
// 2 = DMP configuration updates failed
// (if it's going to break, usually the code will be 1)
Serial.print(F("DMP Initialization failed (code "));
Serial.print(devStatus);
Serial.println(F(")"));
}

// configure LED for output
pinMode(LED_PIN, OUTPUT);

}



// ================================================================
// === MAIN PROGRAM LOOP ===
// ================================================================

void loop() {
// if programming failed, don't try to do anything
if (!dmpReady) return;

// wait for MPU interrupt or extra packet(s) available
while (!mpuInterrupt && fifoCount < packetSize) {
// other program behavior stuff here


}

// reset interrupt flag and get INT_STATUS byte
mpuInterrupt = false;
mpuIntStatus = mpu.getIntStatus();

// get current FIFO count
fifoCount = mpu.getFIFOCount();

// check for overflow (this should never happen unless our code is too inefficient)
if ((mpuIntStatus & 0x10) || fifoCount == 1024) {
// reset so we can continue cleanly
mpu.resetFIFO();
Serial.println(F("FIFO overflow!"));

// otherwise, check for DMP data ready interrupt (this should happen frequently)
} else if (mpuIntStatus & 0x02) {
// wait for correct available data length, should be a VERY short wait
while (fifoCount < packetSize) fifoCount = mpu.getFIFOCount();

// read a packet from FIFO
mpu.getFIFOBytes(fifoBuffer, packetSize);

// track FIFO count here in case there is > 1 packet available
// (this lets us immediately read more without waiting for an interrupt)
fifoCount -= packetSize;

#ifdef OUTPUT_READABLE_YAWPITCHROLL
// display Euler angles in degrees
mpu.dmpGetQuaternion(&q, fifoBuffer);
mpu.dmpGetGravity(&gravity, &q);
mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);


//*********************************************************************************************************************************************************************
//
// PID control based on Pseudocode from https://en.wikipedia.org/wiki/PID_controller
// and the balance point idea from https://www.youtube.com/user/jmhrvy1947

OldP =P; // save value of P
P = (ypr[2] * 1000) + bp; // update P from MPU add bp to correct for balance
OldI = I; // save old I
I = I + (P * 0.05) ;
I = I + ((I - OldI)*2 ); // calulate new I
if( I > 250 ) I = 250; // LIMIT Stop I building up too high
if( I < -250 ) I = -250; // or too low value
D = P - OldP; // D differential change in P
pwm = ( P * 1 ) + ( I ) + ( D * 10 ) ; // P I D

a = 0;
b = 0;
if(pwm < 0){
a = 0;
b = 1;
bp = bp - 0.01;
digitalWrite(13, 0);
}
if(pwm > 0){
a = 1;
b = 0;
bp = bp + 0.01;
digitalWrite(13, 1);
}
/////////////////////////////
// remove sign from PWM as - value has no meaning
pwm = abs(pwm);
if ( pwm < 0) pwm = 0;
if ( pwm > 255) pwm = 255;

if(abs(ypr[2]) < abs(1.1)){
analogWrite(PwmR, pwm);
digitalWrite(PinR1, a);
digitalWrite(PinR2 ,b);

analogWrite(PwmL ,pwm);
digitalWrite(PinL1 ,a);
digitalWrite(PinL2 ,b);
}
else{
analogWrite(PwmR , 0);
analogWrite(PwmL , 0);
I = 0;
bp = -98;
delay(1000);
}

//********************************************************************************************************************************************************
#endif
}
}